Composite glass sandwich panels, consisting of glass face sheets bonded to linear stiffeners (spines) in the core region, can provide significant benefits in material efficiency, reduced thickness, and greater overall transparency. However, current analytical models of their mechanical performance fail to account for the non-uniform longitudinal stress distribution caused by shear-lag effects in wide structural panels. This study redresses this by means of experimental research on composite glazing panels with different loading and geometrical configurations. Six 4-point bending experiments were performed on 34 mm thick, 1000 mm long, and 700 mm wide composite glazing panels, made from soda-lime silica glass face sheets bonded to glass fibre-reinforced polymer core spines. Two types of adhesives were tested: a relatively low stiffness silicone-based adhesive, and a relatively high stiffness epoxy-based adhesive. The shear-lag effects are quantified in terms of effective width ratios (EWR). The study showed that the epoxy-bonded panels provided a significant degree of composite action (DCA = 0.85) whereas the composite action in the silicone-bonded panels was negligible. Furthermore, it was found that applying the EWR values from this study in a recently published analytical model yields predictions of maximum strains at mid-span that deviate by no more than 16 % from the experimental results.

This article has been amended to correct the in-text figure and table referencing and to provide clarification in Table 1 that automotive flat glass production does not take place in the UK. The Supplementary Information has been updated to correct reported units and clarify production processes. The original article has been corrected.

Reuse and high-value recycling have a pivotal role to play in reducing waste and minimising carbon emissions in the built environment. Design strategies for such recovery methods have yet to be fully established in the façade industry. Meanwhile, stringent regulations, aimed at reducing operational carbon emissions of buildings and improving other performance criteria such as occupant safety, have stimulated the use of more complex façade systems that incorporate multiple functions. Other areas of the façade life cycle, such as embodied carbon and high-value material recovery, are rarely considered at the early design stage. This study adopts a mixed-method approach of data collection, to investigate the key challenges and opportunities associated with promoting high-value recovery options for façade products, as perceived by stakeholders in the façade supply-chain. Data was initially collected through an online survey completed by 69 stakeholders from across the façade knowledge/supply-chain. This was followed by 29 semi-structured interviews with selected survey respondents. It emerged that the advancement of circular design strategies is dependent on: increased awareness and quantification of the environmental value of circular design; cross-supply-chain buy-in on developments in take-back infrastructure including greater support for demolition contractors; and advancements in technological separation methods specific to façade components. Enhanced communication between stakeholders - notably between clients, facade contractors and material processors - acceptability criteria and product availability; and more holistic legislation based on whole life cycle emissions, to avoid the over-emphasis on operational efficiency, appear as vital requisites to increasing material efficiency. Finally, we illustrate where stakeholder priorities related to reuse converge and diverge, and thus we identify strategies for levering these factors to minimise environmental impact and optimise economic value in the façade sector.